1. Technical Field
The present disclosure relates generally to ventilation, and more particularly to lung isolation and single lung ventilation.
2. Background Discussion
Lung isolation and single lung ventilation are routinely instituted during thoracic surgery. Surgery involving the lung or the contents of the thorax often requires cessation of ventilation to one lung for two main reasons: 1) to keep the lung immobile while surgery on it is performed, 2) to deflate the lung for better visualization of thoracic structures. Other indications for lung isolation include: 1) containment of unilateral pulmonary bleeding or infection, 2) management of bronchopleural fistula or other pulmonary air leaks. Today, the gold standard for lung isolation is the double lumen endotracheal tube (DLT). Modern disposable polyvinylchloride (PVC) DLTs are modifications of the original Robert-Shaw tube introduced more than sixty years ago. These endotracheal tubes contain two separate lumens, one for each lung, and ventilation is separated with the use of endotracheal and endobronchial balloon cuffs. Drawbacks to the use of DLTs include: 1) difficult insertion due to the device's size and design, 2) need to exchange the tube to a single lumen tube at the end of the case when post-operative intubation is required, and 3) limited compatibility with bronchoscopes and suction catheters due to the DLT's small lumen diameters.
Given these drawbacks, there exists an alternative approach to lung isolation involving balloon tipped endobronchial catheters collectively known as “bronchial blockers.” These devices are deployed through standard large bore endotracheal tubes, utilizing a connector included within the kit. Upon positioning of the balloon tipped catheter into the proper bronchus, balloon inflation leads to unilateral cessation of ventilation. Several variations of this device are currently available for clinical use. Major drawbacks of this device include: 1) inability to quickly and easily alternate ventilation from one lung to the other, 2) easy balloon dislodgement, which not only disrupts lung isolation, but has also led to serious morbidity, 3) inability to suction the isolated lung.
Confirmation of correct placement and positioning of either double lumen tubes or bronchial blockers requires visualization of the tracheobronchial tree anatomy. This is typically achieved utilizing a fiber optic or distal chip pulmonary bronchoscope. Given the possibility of intraoperative dislodgement/malposition, the bronchoscope must remain available for the entire case, tying up considerable resources.